The present invention is directed to so-called intermediate moisture foods which class of foods have long shelf life when stored under non-refrigerated conditions in any moisture impermeable container such as a cellophane wrapper. These foods contain a substantial moisture content yet possess the property of resistance of bacterial decomposition.
Prior art workers, as for example, Burgess, et al. in U.S. Pat. Nos. 3,202,514 and 3,482,985, have provided the concept of packaging nutritionally balanced animal foods with extended shelf life when packaged in any moisture impermeable container, eliminating the need for expensive canning operations. These intermediate moisture foods contain a preservation system which eliminates the need for special techniques such as commercial sterilization incident to the packaging procedure. In intermediate moisture foods, the composition is formulated to preserve against bacteria and fungal growth by employing a combination of water soluble ingredients, such as sugars, salts, sorbitol, propylene glycol, glycerine and other low molecular weight substances in combination with an antimycotic such as sorbic acid and its salts.
The intermediate moisture food components are known to prevent both bacteria and mold growth when the moist food has been stored in any moisture impermeable container. However, due to extended periods of time that the intermediate moisture food may be stored in a container or wrapping such as cellophane, infestation by minute arachnids or mites may take place. Mites thrive on a soft-moist food especially when it is nutritionally balanced and extensive storage times permit undesirable reproduction and growth. The problem of mite control did not occur before the existence of soft-moist intermediate moisture foods which have an ideal moisture content for mites. Storage for long time periods at room temperature rather than in a cooler or freezer and in any moisture impermeable wrapping material has prompted a need for controlling mites without resorting to chemical insecticides which are not compatible for food utility.